Claude Code Authentication Issue

[ederson-morche]

Describe the bug
I'm getting the following error when I try to use an agent powered by Claude Code:

⚠️ I couldn't process the last request: authentication failed. Please re-authenticate the CLI (e.g. run claude /login or codex login) and then re-send.

I tried sign out and in again in the Claude Desktop and restarting both Claude and Buzz but no success.

Steps to reproduce

1. Trigger Agent that's using Claude harness
2. System will throw some errors on agent view
3. Agent will report the error back

Expected behavior
It was working until a couple of days ago.

Version and platform

• Buzz version: 0.5.11
• OS: MacOS 26.5.2